Why did William Branham claim his "seven church age" timeline came by both "revelation" and "handwriting by an angel," when years earlier he confessed that he copied the timeline from others? Why is the cult indoctrinating children with his false claims?

One might argue that Branham also added "messengers" to the dates he copied from Larkin, and that this was "divine revelation." If so, why were mistakes made? Why were some "messengers" not alive during their "church age?"